--- a/devtools/client/framework/toolbox.js
+++ b/devtools/client/framework/toolbox.js
@@ -3380,21 +3380,32 @@ Toolbox.prototype = {
    * to true.
    * @see browser/components/extensions/ext-devtools.js
    */
   isWebExtensionEnabled: function(extensionUUID) {
     const extInfo = this._webExtensions.get(extensionUUID);
     return extInfo && Services.prefs.getBoolPref(extInfo.pref, false);
   },
 
+  /**
+   * Returns a panel id in the case of built in panels or "other" in the case of
+   * third party panels. This is necessary due to limitations in addon id strings,
+   * the permitted length of event telemetry property values and what we actually
+   * want to see in our telemetry.
+   *
+   * @param {String} id
+   *        The panel id we would like to process.
+   */
   getTelemetryPanelNameOrOther: function(id) {
     if (!this._toolNames) {
       const definitions = gDevTools.getToolDefinitionArray();
       const definitionIds = definitions.map(definition => definition.id);
 
       this._toolNames = new Set(definitionIds);
     }
+
     if (!this._toolNames.has(id)) {
       return "other";
     }
+
     return id;
   },
 };

--- a/devtools/client/inspector/toolsidebar.js
+++ b/devtools/client/inspector/toolsidebar.js
@@ -327,31 +327,62 @@ ToolSidebar.prototype = {
    *         id of the previously selected tool.
    */
   updateTelemetryOnChange: function(currentToolId, previousToolId) {
     if (currentToolId === previousToolId || !this._telemetry) {
       // Skip telemetry if the tool id did not change or telemetry is unavailable.
       return;
     }
 
+    currentToolId = this.getTelemetryPanelNameOrOther(currentToolId);
+
     if (previousToolId) {
+      previousToolId = this.getTelemetryPanelNameOrOther(previousToolId);
+
       this._telemetry.toolClosed(previousToolId);
 
       this._telemetry.recordEvent("devtools.main", "sidepanel_changed", "inspector", null,
         {
           "oldpanel": previousToolId,
           "newpanel": currentToolId,
           "session_id": this._toolPanel._toolbox.sessionId
         }
       );
     }
     this._telemetry.toolOpened(currentToolId);
   },
 
   /**
+   * Returns a panel id in the case of built in panels or "other" in the case of
+   * third party panels. This is necessary due to limitations in addon id strings,
+   * the permitted length of event telemetry property values and what we actually
+   * want to see in our telemetry.
+   *
+   * @param {String} id
+   *        The panel id we would like to process.
+   */
+  getTelemetryPanelNameOrOther: function(id) {
+    if (!this._toolNames) {
+      // Get all built in tool ids. We identify third party tool ids by checking
+      // for a "-", which shows it originates from an addon.
+      const ids = this._tabbar.state.tabs.map(({ id: toolId }) => {
+        return toolId.includes("-") ? "other" : toolId;
+      });
+
+      this._toolNames = new Set(ids);
+    }
+
+    if (!this._toolNames.has(id)) {
+      return "other";
+    }
+
+    return id;
+  },
+
+  /**
    * Show the sidebar.
    *
    * @param  {String} id
    *         The sidebar tab id to select.
    */
   show: function(id) {
     this._tabbox.removeAttribute("hidden");